A Method of Amplitude Preserved RTM for VSP Angle Domain Gathering

This paper introduces the method of generating angle-domain common-image gathers (ADCIGs) by VSP RTM. We modify the equations used to backward propagate receiver wavefield, and then compare the relative amplitude preservation of the ADCIGs. Using a simple model with four horizontal layers, the ADCIGs generated by different types of VSP wavefields (including up-going waves, down-going waves, and direct waves et al.) and the corresponding noise on the angle gathers is analyzed. Finally, this method is also applied to a real VSP data, and the results show that this method is accurate and feasible. The angle gather has a wide range of application, which can offer potential for VSP migration velocity analysis, AVA/AVO analysis and elastic inversion.